C/C++ Question Pass reference/instance of an existing B4R library to constructor

Johan Schoeman

Licensed User
RLiquidCrystal is an existing library in B4R. How would one wrap the below constructor to pass it to a wrapper for LcdBarGraph and how would one then pass rLiquidCrystal from B4R to LcdBarGraph?

// -- constructor
LcdBarGraph::LcdBarGraph(LiquidCrystal* lcd, byte numCols, byte startX, byte startY)


Staff member
Licensed User
1. You need to use the placement constructor. See how B4RLiquidCrystal::Initialize is implemented. Specifically the use of (backend).

2. Your class should accept a B4RLiquidCrystal parameter and then get the hidden (see the h file) public lc field.